Why don't you get a premade tank or XXL Exo-terra. I cut a hole in the side of my hex tank. If I ever did it again, and I seriously mean IF! I would drill the corners with a small diamond hole saw (ebay). I used a Dremel and 3 bits and modeling clay to make trough for water. To make a 9"x11" hole and it only took me like 5 hours and 6 beers. The dangerous part is the glass your cutting out, at the very end it will drop. Possibly cracking the pane or falling into the tank. Mine got a minute crack as the glass dropped like 3/8".